Clostridium difficile infection in rural Ontario: a retrospective multisite population-based study.

INTRODUCTION: We conducted a retrospective, population-based study to assess the prevalence of Clostridium difficile infections and the associated risk factors among inpatients and outpatients in our region.

METHODS: We used laboratory data over a 2-year period to identify inpatient and outpatient cases of C. difficile infection. Data were collected from 3 local catchment areas for rural hospital laboratories in Sioux Lookout, Mount Forest and the South Huron Hospital Association in Exeter. We gathered demographic data and infection-specific information, including recent antibiotic use and recent or current hospital admission or nursing home stay.

RESULTS: During the study period, 34 cases of C. difficile infection occurred in 29 patients, with an estimated crude annual rate of 24.3/100,000 population. Of the cases, 47.1% were diagnosed in outpatients. Most patients (76.5%) had taken antibiotics within the previous 90 days, and antibiotic use and hospital admission accounted for 47.1% of cases. Clindamycin was more commonly associated with C. difficile infections at the northern site and ciprofloxacin at the southern sites. There were 2 deaths from comorbidities.

CONCLUSION: The estimated annual incidence of C. difficile infection in our study is similar to urban-based estimates. Almost half of the cases involved outpatients, indicating a need to recognize this illness as a serious outpatient condition. Antibiotic stewardship is an ongoing consideration, as most patients were exposed to antibiotic use before infection.